DE2554281A1 - METHOD FOR MANUFACTURING HOLLOW BODIES FROM PREFORMS FROM PLASTIC MATERIAL, HOLLOW BODIES PRODUCED ACCORDING TO THIS METHOD AND PREFORMS FOR THE MANUFACTURING OF SUCH HOLLOW BODIES - Google Patents

Description

Oarnaud! Total Interplastio, Rue Eaul Sabatier »3Γ-7ΠΟ6 Chaton-

su r-Saone, France

Process for the production of hollow bodies from preforms made of plastic material, produced according to this process Hollow bodies and preforms for the production of such hollow bodies,

The invention "relates to a method of manufacture of hollow bodies made of thermoplastic material as well as hollow bodies that are produced by this process.

Various processes are already known for the production of hollow bodies made of thermoplastic material, such as bottles or small bottles, an extrusion or injection process initially producing a preform which is then inflated inside a generally two parts existing blow mold is stretched _o

It is already known to stretch such preforms at a temperature high enough to allow biaxial stretching to achieve a material condition referred to as the bi-oriented condition, wherein the preform is stretched once and then it is then cooled so that the state of the double orientation of the material, which is reached during the stretching process This state of double orientation gives the material particularly interesting properties in terms of resistance and mechanical durability,

However, these hollow bodies have the disadvantage that they have a relatively high weight, which is particularly due to the material

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due concentration at specific locations of the body, particularly in the area of the neck is _o In addition, the material in the known hollow bodies different states depending on the respective positions on what paint to various shopping "and properties, in particular for the mechanical behavior of the tightness and which led to temperature resistance

For example, the French patent application 73 26523 of Mitsui Toatsu Chemicals Incorporated describes a process for the production of hollow bodies by blowing with double-axial orientation, starting from a blank in the crystalline state and the stretching processes being carried out at a temperature which is above the point of This crystalline fusion liegte obtained crystalline hollow body, but uecke _r for greater internal D little suitable.

The American patent 3,202 _o 739 (Zavasnik) also describes a method which is similar to the previous one, the hollow bodies obtained also having defects in terms of homogeneity.

French patent application 69 095 * 15 (Hercules Incorporated) also describes a process for the production of hollow bodies, in which the deformation that occurs at high temperatures « door is carried out, leads to a hollow body that is not homogeneous.

This also applies to the US Patent 3 x 754 _ο 851 (Reilly Sincock), which describes a method for the production of hollow bodies, wherein a blank, which is held in the region of the ring or neck, produces overall by blowing of a material which lacks homogeneity and which therefore has insufficient resistance when used under difficult conditions _o

The present invention proposes to specify a method for the production of hollow bodies from thermoplastic material, these disadvantages are avoided and in particular light hollow bodies arise that have a great resistance and have a much more homogeneous material state, whereby the Differences in the behavior of the various parts of the hollow body are avoided and the homogenization of the qua · «· properties of the entire hollow body are improved «.

The invention relates to a method for the production of hollow bodies made of thermoplastic material, initially a Preform is made from preferably amorphous thermoplastic material, which is then stretched to then produce the final To obtain the shape of the hollow body, this method being characterized in that the preform has a temperature is exposed to greater than or near the temperature of the transition of the thermoplastic material into the vitreous State is, and that the entire hollow body is then stretched until a double orientation of the entire hollow body is achieved is, after which the material solidifies in a double-oriented state

With the entirety of the hollow body of the whole hollow body including the neck, or other upper constriction is meant an exception, if appropriate, only a central region which is limited of the hollow body through the bottom _o

In this way a hollow body is obtained in which almost all of the material including the material is in the area of the eventual. Neck or an upper constriction in a state of double orientation with the special features in terms of resistance and durability

With the help of the invention it is possible to achieve a considerable reduction in weight while maintaining the same resistance for the hollow

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body because the neck or the upper constriction of the Hollow body has a double-oriented state, so that this can also have a significantly smaller thickness than is necessary for a neck which, according to the prior art, was in a non-double-oriented state

According to the invention, the temperature to which the blank is fed is between 0 and 30 ° above the temperature of the transition of the thermoplastic material in question into the glass-like state.

According to the invention, a hollow preform is produced, preferably tubular in shape, the diameter of which over its entire Cross-section is substantially smaller than the diameter which, in the case of the finished hollow body, in the relevant cross-section is realized. The diameter of the hollow body is preferably at least 1.3 times in a certain cross section larger than the diameter of the preform, but with a Elongation that is at least 1.5 times greater is particularly preferred.

In a preferred application of the invention, the preform is manufactured in such a way that it has a part of material above its neck or mouth which, for example, originates from the manufacture of the preform and enables the preform to be transported and held during the blowing or expanding, after which this material part is then cut off and fed back into the cycle _o

In a particularly advantageous embodiment of the invention, a polymer is used for the production of the preform Material with a crystalline state, the preform solidifying with an amorphous structure and the deformation this preform is carried out at a temperature which is close to and above the temperature of the transition into the glass arti «·

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state, with a degree of expansion being used which is sufficiently large to produce a double-oriented material. tending to create, after which this state is quickly frozen by recooling.

The polymeric materials used include in particular the thermoplastic polyesters, for example the polyterephthalate of ethylene glycol, the polyterephthalate of tetramethylene, the polyterephthalates of butylene, the copolymeric terephthalates / isophthalates of cyclohexylenedimethylene; they also form the Polyamides and the polyacetates and especially the polyoxymethylene

The thermoplastic polyesters, the expansion is carried out so that it leads to an increase in the diameter of the entire cross section of the hollow body, which is more than 1 _f 5 times the original diameter, so as to obtain a double-oriented state ·

In a first preferred embodiment of the method according to the invention, in which the expansion is carried out inside the blow mold, the temperature of the material is controlled during the expansion so that it is constantly equal to or above the temperature of the transition to the glass-like state, which is Freezing of the double-oriented state on the cold walls of the blow mold results in _o

The finished hollow body is preferably subjected to heat setting by increasing the temperature of the material after the intervening existing constrained states are lifted are.

In another embodiment that can be carried out particularly quickly, the preform is expanded inside the blow mold at a material temperature that is initially above and

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then below the temperature for the transition to the vitreous state, which leads to the freezing of the constrained bonds of the double-oriented state during the last part of the expansion, the blow mold preferably being kept at such a temperature that the material is in contact with it the final heat setting is ensured on the hot walls of the blow mold _o

It is also possible in the case of a hollow body that is not conclusive Was subjected to heat setting, this heat setting by simply filling the hollow body with a product, such as a liquid, especially to be carried out under pressure at an elevated temperature

The heat setting occurs in particular at a temperature which is well above the temperature of the transition to the glass-like state, so that the heat setting then is going on at as high a rate as possible.

The invention also relates to a hollow body which was produced using the method according to the invention, this being Hollow body is characterized in that it basically has a double-oriented state over almost its entire area of the material

The hollow body, which is made of polymeric material with crystalline Structure obtained are also characterized in that they may be on almost all of the material of the hollow body with the exception of the central area of the bottom, have a material state with double orientation, the material is transparent, rigid, resistant and waterproof and also has excellent temperature resistance ο So it is possible to use the hollow bodies, which are made of this material, for the storage of products

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at an elevated temperature, for example for products with a sterilization temperature inside the hollow body _{or the like}

It is also possible for the hollow bodies produced reuse by being subjected to sterilization, with the same conditions as applied for hollow glass who «the _o

The invention also relates to the preforms for the manufacture "development of the hollow bodies of the invention, said preforms are particularly characterized in that its radial dimensions are smaller than the radial dimensions of the finished hollow body and in such a size that the hollow body almost to its Entire state of double orientation, the preforms preferably having an extension at their mouth or neck which is scrap at the end of the expansion process _{or the like}

The invention particularly relates to the preforms made of the crystalline polymeric material which are characterized are that the material of the preform is in an amorphous state, which is due to vigorous re-cooling is achieved, this re-cooling takes place from the plasticizing temperature.

Further advantages and characteristic features of the invention will become apparent from the following description, which relates to a refers to a particular embodiment, but does not represent a limitation of the inventive concept

Show it:

1 is a schematic view of an apparatus with which the method according to the invention can be carried out;

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2a / and 2b a preform according to the invention, which indicates two stages of its manufacturing process;

Fig. 3 is a section through a blow mold with which

a step of the manufacturing process according to the invention can be carried out, wherein the Form has a preform, which by Bla « sen should be expanded

In the phase denoted by 1 in FIG. 1, a mass of thermoplastic polyester, for example polyterephthalate-ethylene glycol, is extruded by a conventional extrusion process, as a result of which the bonded material of the mass is plasticized. The bound material of the mass is homogeneous and changes to a liquid state at a temperature which is close to its melting temperature. "For this purpose, a double extrusion screw according to L Andouart, which is known in the prior art can be used." Their characteristic features consist in a diameter of? Screw of 120 mm, a length of the supply screw of 15 D _{1 and} a length of the plasticizing screw of 15 D, the drives of the screws being independent of one another. The output of such an extruder is approximately 300 kg / hour.

For the material used, the melting temperature is 257 ° C and the mass leaves the extruder at one temperature between 260 ° 0 and 290 ° 0 «

The mass can also be made by other methods, especially by injection

Starting from this mass, in the phase shown in Fig. 1 is denoted by 2, a preform according to the invention.

To do this, the mass is subjected in a blow mold to a blowing process, wherein the blow mold has a cavity corresponding to the desired preform and the walls of which are strongly cooled again _o In this blow molding, the composition is expanded by introducing a heat-regulating fluid under pressure until it adapted itself precisely to the shape of the cavity of the blow mold. When the cold walls of the cavity of the blow mold are touched, the preform cools down considerably again, which makes it possible for it to acquire an amorphous structure.

In this way, a preform as illustrated in FIG. 2a of the drawing is obtained. This preform has a hollow portion extending over a portion of DI This is extended at its upper part by a he "far Erten portion which extends over a piece of D2, to be referred as a false ring _o This is a part extended, which is located at its upper end D3 and is hereinafter referred to as wasteo

The preform leaving the blow mold, which is designated by 3 - net, then passes through a cutting device 4 in FIG. 1, this device separating the upper waste part from the remainder referred to as the preform, which is denoted by 5 in FIG. 2b and consists of a tubular body extending over the area DI and an upper part, which is expanded in relation to the body, which is called the false ring and which extended over the section D2 The preforms 5 obtained in this way are then optionally stored in the store 6.

The preforms according to the invention are then subjected thermi "- subjected see * treatment which must be homogeneous con- _o For this purpose, the preforms of a device 7 are fed in which they heating elements, in particular via conduction,

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be exposed vection or radiation, which takes a predetermined time to reach a! temperature which is greater than and close to the temperature at which the bound material of the preform in a glassy state transitions _o In the example considered, in which the preform of Polyterephthalate ethylene glycol, the preforms are heated to approximately 70 ° C.

A tunnel oven equipped with infrared heating elements can be used to carry out this thermal treatment. tet is, in which the preforms are rotated on a mechanical transport device 8, which is provided with means is to turn the preforms on it so that they device expose its entire circumference.

The preforms, which are thus heated to a temperature which is close to or above the temperature of the transition of the material to a vitreous state, are then picked up by a transfer device 9 which is able to quickly feed the hot preforms to a blower , which is generally designated 10 _o

The transfer device can consist, for example, of a gear provided with an arm, which performs an alternating movement with an amplitude of 180 °, which enables the preforms to be transported fully automatically into the blow mold _{or the like}

In the blow mold, the preform is stretched until it assumes the shape of a hollow body 11, which corresponds to the final shape. speaks, with the exception of an upper part, which is removed with the aid of a cutting device 12 until the final term shape of the hollow body 13 receives.

From FIG. 3 it can best be seen how the preform 5

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is expanded until it has the shape 11 of the vial _o The blow mold 14 · is provided with a heat control circuit 15, which includes a device for axially expanding the parison, which is generally designated 16 and which allows the parison 5, its 3, a device is schematically denoted by 17 which enabled the introduction of a fluid for inflating the preform into the same. The blow mold must also be provided with means for locking and means for automatic actuation be".

The blow mold has in Fig. 3 a part 18 which corresponds to the neck of the hollow body in the form of a little bit in its final shape. This part 18 is extended in its upper part over a part 19, the shape of which corresponds to the shape of the false ring to which the preform is connected _{or the like}

The parts 18 and 19 are connected to one another via an edge 20, which makes it possible to form a zone of weakness in order to to facilitate the removal of the upper part, which corresponds to the wrong ring, from the final hollow body ·

When the preform 5 is expanded to the inside of the blow mold 14 is, the preform 5 is extended over its entire part, which should form the final shape of the bottle, in particular on the part corresponding to the cavity 18, which is intended to accommodate the neck of the bottle to be created. chens · This ensures expansion and double orientation of the entirety of the hollow body obtained.

As already explained above, the mold cold walls aufwei- sen _o In this case, the temperature of the material during expansion of the preform is controlled so that this temperature is always equal to or greater than the temperature of the transition in the glassy region. When leaving the blow mold

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255A281

the hollow body is subjected to a heat set treatment, by raising the temperature of the material to the meantime occurring phenomena forced aside _o

For the material mentioned, the temperature for thermo · * fixing is approximately between 180 ° 0 and 200 ° C ₀

It is also possible to expand the preform inside the blow mold at a temperature of the material which is first above the temperature of the transition to the glassy state and then below this temperature, which during the last part of the expansion causes the constraints of the double-oriented state to solidify, and the blow mold is kept at a temperature which enabled the heat setting to be carried out. The heat setting can also be achieved by simply filling the hollow body with a product, such as a liquid, in particular be carried out under pressure at an elevated temperature.

The invention has been described on the basis of a particular form of embodiment. However, it is in no way limited thereby and all modifications, in particular with regard to the shape or the materials, can be made without the frame or to leave the gist of the invention.

Expectations

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Claims (1)

A η s ρ r ü Process for the production of hollow bodies from thermoplastics chem material, first being a preform made of thermoplastic Material is produced, which is then stretched in order to obtain the final shape of the hollow body, characterized in that the preform is reheated to a temperature above or near the The temperature of the transition of the thermoplastic material into a vitreous state and that then the entire hollow body is stretched by blowing until a double orientation of the entire hollow body is achieved, after which the material is made to freeze in the state of double orientation ο 2) Method according to claim 1, characterized in that the temperature to which the preform is made, lies between ⁰ and 30 ° 0 above the temperature at which the thermoplastic material in the glassy Z _u stand passes _o 3) Method according to any one of claims 1 and 2, characterized in that that the hollow preform has in particular a tubular shape with a bottom, the diameter of the entire cross-section is essentially smaller than the diameter which, in the case of the finished hollow body, in the corresponding one Cross-section is achieved. 4-) Method according to claim 3 »characterized in that the diameter of the hollow body in a certain cross section is at least 1.3 times larger than the diameter of the preform, preferably 1.5 times larger _o 5) Method according to any one of the preceding claims, that - 14- - 6 U 9 characterized in that the preform is produced in this way is that he has a part of material beyond his neck or mouth, which in particular of the Production of the preform comes from and the transfer and holding of the preform during the turning process ganges allows, after which this part is then cut off and reused. 6) method according to any one of the preceding claims, characterized in that the preform is made of a polymer Material is produced with a crystalline state, wherein the preform solidifies in an amorphous structure and the Deformability of this preform is achieved at a temperature that is close to or above the temperature of the above ** gangs lies in the glass-like area, with a degree of expansion that is large enough to double- to create oriented material state and that then quickly solidification of this state by recooling is carried out", 7) Method according to claim 6, characterized in that a thermoplastic polyester is used _o 8) Method according to claim 7 »characterized in that a polyterephthalate ethylene glycol is used. 9) Method according to any one of claims 7 and 8, characterized characterized in that the inflation is formed so as to increase the diameter of the whole Cross section of the hollow body results, which is larger than 1.5 times the original diameter of the original double-oriented state so 10) method according to any one of the preceding claims, characterized in that the elongation of the preform - 15 - 9-8 24/0755 is carried out inside a blow mold, with the temperature the material is so controlled during stretching., that it is always equal to or greater than the temperature at which the material changes to the glassy state, the Solidification in the double-oriented state occurs on the cold walls of the blow mold «, 11) Method according to claim 1O _5, characterized in that the finished hollow body is subjected to heat setting by increasing the temperature of the material «, 12) Method according to any one of claims 1 to 9 »characterized in that the stretching of the preform inside the blow mold is carried out at a temperature of the material which is initially above the temperature at which the Material goes into the glassy state and then below this temperature, which occurs during the second stage of the The stretching process then causes the compulsive phenomena of the double-oriented state to solidify. 15) Method according to claim 12, characterized in that the blow mold is held at a temperature which makes it possible that during the contact of the material with the Walls of the hot blow mold the final heat setting is carried out «, 14) Method according to claim 12, characterized in that the heat setting by filling the hollow body with a pro « duct, for example a liquid, especially under pressure at an elevated temperature «, 15) Method according to any one of claims 11 to 14, characterized in that the heat setting takes place at a temperature of the material results, which is well above the temperature at which the thermoplastic material in the - 16 - 609824 / 07S5 - 16 -
glass-like condition übergelrfco 16) hollow body, in particular bottle or vial, which, respectively which is produced according to any one of the preceding claims, characterized in that it, or it has a double-oriented state of the material in almost the entire hollow body. 17) preform for the production of a hollow body according to claim 16, characterized in that its radial dimensions are smaller than the radial dimensions of the finished one Hollow body, in a size that the hollow body is almost in its entire area in a state of Double orientation is located. 18) Preform according to claim 17 »characterized in that it has an extension from its mouth or from its neck, which is part of waste at the end of the stretching process . Blank page